Breech block return means for the browning machine gun



Sept. 21, 1948. c, E sE 2,449,545

BREECH BLOCK RETURN MEANS FOR THE BROWNING MACHINE GUN Filed Jan. 25, 1945.

cxmvmmw Wm Patented Sept. 21, 1948 BREECH LBLO CK ilt'ETURNaMEAN S :FOR THE BROWNING MACHINE GUN Charles'ELBalleisen, Philadelphia, Pa. Application January 25, 1945, Serial No. 574,600

(Grantedxun'der the act of March 3, 1883, as amended April-J30, 1928:; 370 0. GU15?) 2 Claims.

the use of the'driving, or reaction spring in a machinegun.

Other purposes of the invention will become apparent 'fromthe following description and drawings. I

A preferred embodiment of the invention "has been shown and illustrated in the drawing-in which:

The figure shows a sectional elevational view of a machinegun including-the invention.

In the drawing I have illustrated a 'firearm'in many respects similar to tha-t disclosed i'n the Browning Patent 1,293,021, dated February 1919. Reference may'be'ha'd' to'the said patent for'various details'of construction of the firearm-not herein otherwise disclosed. It'is to 'be understood, however, that the reference to the above patents i's'n'ot to "be construed as limitingthe scope of the presentinvention'as set forth and claimed herein.

Referring to Patent No. 1,628,226 it will be seen that Figure 12 thereof shows a reactionspring'36 coiled around a guide rod 31*. In-Figure'IIZE of Patent No.*1-',2'93',021, a reaction spring R is coiled around a guide rod r. It isproposed as an important part otthisinventi'on to elimimate the use of these reaction springs and guide rods for high speed machine guns of the type disclosed in the two mentioned patents.

Inmachine guns of thetype shown in the two above mentioned patents, a reciprocating breech bolt is provided, which during, recoil is thrown against the bufier plate behind which are containeda number of resilient washers or a coiled spring. During this rearward movement the bolt also serves to compressthe reaction spring against theback plate. As the bolt jthus recoils, its-kinetic'energy is absorbed by the reactionspring and by-the resilient member includingthe buffer plate and the resilient washers. The bolt is thus brought to rest at its rearwardmost position.

The resilient washers and reaction spring having been compressed by the bolt, now expand against 'thebolt, thereby returning to it some of the energyreceived from it, and" thus cause the bolt tomove forward in counter recoil.

The reaction spring; according to thesaid patents, is supposed to continue to urge the'bolt forward during counter-recoil and inorder to performthis function the springrmust have-one end in constant contact with the bolt during counter-recoil.

It has been observed from photographic records of machine guns of'thistypefiring'at a high 'rate of fire, that the reaction spring. exerts little, if any, effect upon the motion of the bolt; When firing the Browning .50'calib'er machine gun at a rate of'fire of approximately BOO-rounds per minute or more, the bolt" velocity has been found to be uniform from the time itis unlocked from the barrel on; recoil until itstrikes against the bufier-pla-te, and also during counter-recoil, until it is again locked on 'tothe barrel.

During tests the driving or reaction spring. has been removedirom a .50 caliber Browning machinegun'. The gun was then fired at zero elevation, at 'a'highangle'of elevation, and at a large angle-of depression. No appreciable dinerence was noticed in the rate of fire in" any ofth'ese positionsor when the reaction spring was-replaced-inthe gun.

It is thus apparentthat itisnot necessary in the high speed machine gun to have areaction spring ofwhich one end'is in constant engagementwith' the reciprocating? bolt in order" to're- Z-urnthebolt to its forwardmost or battery posiion.

Accordingly the usual driving spring. also known the reaction spring; may -be' removed from thehighspeed machine gun, and th'egun will continue to fire satisfactorily; the-boltoperating in free flight and 'reboundingf'rom the back plate for counter-recoil.v "Inasmuch 'asthe -construction and'function.- ing of 1 the-Browning machine guns i's quite adequatelydescribed in great detail in both of the above mentioned patents, it is not deemed; necessary to repeat all'the .contentsiof said patents' inthis application. Instead, there has been.

3 Other details have been omitted solely for clarity and are not required to be dispensed with in a gun employing the present invention.

Referring now to the drawingof the present application, it is seen that there is] a breech bolt E fitted to move in the barrel extension C and in the breech casing A in the rear of the extension. The breech bolt has ribs in its sides which are guided in corresponding grooves in the barrel extension. The rear end of the breechbolt in its rearmost position is guided upon the breech bolt guide F, located in the lower rear portion of the casing A.

When the cartridge is fired, the barrel barrel 7 extension 0 and bolt E being locked together, recoil together as a unit for a, short distance when,

as is well known, the rearward motion of the.

barrel and barrel extension is halted and the breech bolt E is unlocked from them. The bolt, assisted by the action of the accelerator or rock-. ing lever O, continues its rearward recoiling motion until it strikes sharply against the buffer plate It the reduced front end of which projects through a corresponding hole in the rear platelso as to stand in thepath of the breech bolt. In the hollow handle K of the gunbehind the buffer plate is, there are placed a number of washers of-resi1ient material, as describedin the said Patent No. 1,293,021.

Since in accordance with the present invention there is now no reaction spring R, the

recoiling bolt -Ei does not have any of its energy absorbed, except by friction, until it strikes sharply against the buffer plate k. The bolt E then rebounds sharply from the buffer plate is and counter-recoils to its forward position where it is again in the usual cooperative relationship with vthe barrel B. c

. The removal of the usual reaction spring R has the added advantage of decreasing the number of parts requiring maintenance since it is not present to be continuouslyloaded and unloaded with consequent deterioration. I

. Since the recoiling bolt E is no longer required to be under the constant retarding influence of a reaction spring, the bolt may be considered to recoil in substantially free flight and thus to recover a considerable portion of its kinetic en'- ergy in rebounding from the buffer plate It into counter-recoil. It has been found that this energy recovery is quite sufficient to permit the bolt E to perform its usual counter-recoil functions.

It is to be understood of course, that the bolt mustinitially be set in the closed position against therear end of the barrel, or returned to that position after a malfunction. That action may be performed manually or by an auxiliary. spring on an external charger. t

From the foregoing description it is apparent that the present invention has eliminated the usual driving spring from this type of vmachine gun, thereby dispensing with one moving part which is constantly being stressed and released from stress, thus avoiding the maintenance problem's encountered when the spring is used. It will be observed that when the reaction spring is omitted, the buffer plate functions as an'anvil against which the breech bolt strikes sharply and rebounds into counter-recoil. The space between 4 the rear of the breech-bolt and the buffer plate is thus left unobstructed so there is no impedance interposed to the free movement of the bolt until it strikes against the buffer plate itself.

.portion of the breech casing, a breech-bolt slidably mountedin said casing independently of said barrel and buffer means, said breech-bolt being freely movable rearwardly from said barrel on recoil toward the rearward portion and forwardly on counter-recoil away from the rearward portion towards the barrel, said barrel and said buffer means forming the limits of travel of said breechbolt, said breech-bolt striking against said elastic buffer means on recoil and rebounding from said means in counter-recoil into cooperative relationship with said barrel, said buifermean's being the sole means for absorbing the shock of recoil of the breech-bolt by arresting recoil movement thereof and for returning the breech-bolt to cooperative relationship with said barrel by imparting counter-recoil movement to the breech-bolt.

, 2, In a machine gun having a breech casing, a barrel mounted in said casing for motion rearward during recoil and forward during counterrecoil,= a reciprocating breech bolt releasably locked to said barrel during its said recoil and r counter-recoil movements thereof, means for arrestin the rearward motion, of said barrel at a predetermined point and unlocking said breechbolt therefrom, and means for thereupon accelerating the rearward motion of said breech-bolt,

the combination therewith of an elastic member mounted in the rearward portion of said casing and so constructed and arranged for arresting the rearward motion of said bolt and for causing the same to rebound in counter-recoil forwardly into cooperative relationship with said barrel, said elastic member being the sole means for absorbing the shock, of recoil of the breech-bolt by arresting the rearward motion of the same and for imparting counter-recoil movement to said bolt to return the same into cooperative relationship with said barrel.

CHARLES E. BALLEISEN.

1 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 7 Date 755,482 Halle ,Mar. 22, 1904 1,293,021 Browning Feb. 4, 1919 1,446,635 Berthier Feb. 27, 1923 2,108,026 Sutter et a1 Feb. 8, 1938 2,306,633 McCrumb Dec. 29, 1942 2,322,780 Gorton June 29, 1943 

